Finding the Equation of a Line

Finding the equation of a line means writing the rule that every point on a straight-line graph obeys, such as \(y = 2x + 1\). In NSW Year 8 maths this is done by reading points into a table, while gradient and \(y = mx + c\) wait until Stage 5 (NESA outcome MA4‑LIN‑C‑01).

You will read coordinates from a graph, find how much \(y\) changes for each step across and the value of \(y\) when \(x = 0\), then write and check the rule. You will recognise horizontal lines like \(y = 3\) and vertical lines like \(x = 3\), handle decreasing lines and points that are unevenly spaced, and use the rule to extend a line, for example to model a pool being filled or the distance left in a kayak race. It is part of Year 8 Graphing Linear Equations.